1. Field of the Invention
In one of its aspects, the present invention relates to an on-line device for predicting at least one fluid flow parameter in a process. In another of its aspects, the present invention relates to an on-line UV dosimeter for predicting bioassay equivalent does for a given microorganism in a UV disinfection process. In yet another of its aspects, the present invention relates to a method for on-line prediction of at least one fluid flow parameter in a process.
2. Description of the Prior Art
Fluid treatment systems are known generally in the art.
For example, U.S. Pat. Nos. 4,482,809, 4,872,980 and 5,006,244 (all in the name of Maarschalkerweerd and all assigned to the assignee of the present invention and hereinafter referred to as the Maarschalkerweerd #1 Patents) all describe gravity fed fluid treatment systems which employ ultraviolet (UV) radiation.
Such systems include an array of UV lamp frames which include several UV lamps each of which are mounted within sleeves which extend between and are supported by a pair of legs which are attached to a cross-piece. The so-supported sleeves (containing the UV lamps) are immersed into a fluid to be treated which is then irradiated as required. The amount of radiation to which the fluid is exposed is determined by the proximity of the fluid to the lamps, the output wattage of the lamps and the fluid""s flow rate past the lamps. Typically, one or more UV sensors may be employed to monitor the UV output of the lamps and the fluid level is typically controlled, to some extent, downstream of the treatment device by means of level gates or the like.
U.S. Pat. Nos. 5,418,370, 5,539,210 and 5,590,390 (all in the name of Maarschalkerweerd and all assigned to the assignee of the present invention and hereinafter referred to as the Maarschalkerweerd #2 Patents) all describe fluid treatment systems which employ UV radiation. More specifically, the Maarschalkerweerd #2 Patents teach an ultraviolet radiation treatment system disposed in an open channel comprising a gravity fed flow of fluid. In a preferred embodiment, after treatment, the fluid is then discharged into a stream, creek, river, lake or other body of waterxe2x80x94i.e., this embodiment represent application of the system in a municipal wastewater treatment facility.
Conventionally, in the art of UV radiation treatment systems, the radiation dose in a given irradiation zone has been calculated using the equation:
DOSE=tavexc3x97Iave 
wherein tave is the average time that a microbe spends in the irradiation zone and Iave is average UV intensity integrated over the volume in the irradiation zone.
Recently, it has been suggested that this relatively simple calculation can, in certain cases, lead to inaccuracies in the dose which is actually delivered to the fluid being treatedxe2x80x94see xe2x80x9cHydrodynamic behaviour in open-channel UV systems: Effects on microbial inactivationxe2x80x9d (K. Chiu, D. A. Lyn, and E. R. Blatchley III, CSCE/ASCE Environmental Engineering Conference (1997), pages 1189-1199). This can have significant consequences since many UV radiation treatment systems are specified in large part using such a calculation. Further, the calculation presumes that the system is operating in an optimum state at all times and thus, for example, would not take into account a situation where one or more of the UV radiation sources is not operating properly or at all.
Accordingly, there remains a need in the art for a device which would allow one to predict with improved accuracy the dose delivered to the flow of fluid. It would be advantageous if such a device had widespread use beyond that in predicting (lose delivered to a flow of fluid in a UV radiation treatment systemxe2x80x94i.e., beyond use as a dosimeter.
It is an object of the present invention to obviate or mitigate at least one of the above-mention disadvantages of the prior art.
It is another object of the present invention to provide a novel on-line device for predicting at least one fluid flow parameter in a process.
It is another object of the present invention to provide a novel method for on-line prediction of at least one fluid flow parameter in a process.
In one of its aspects, the present invention provides an on-line device for predicting at least one fluid flow parameter in a process, the process comprising a bounded flow domain having disposed therein a pre-determined matrix, the device comprising a computer having:
(i) a memory for receiving a database, the database comprising location information for a plurality of nodes or particle pathways in the matrix,
(ii) means to receive input data from the process, and
(iii) means to calculate the at least one fluid flow parameter from the database and the input data.
In another of its aspects, the present invention provides an on-line device for predicting at least one fluid flow parameter in a process, the process comprising a flow domain having disposed therein a pre-determined portion in which a fluid flows, the device comprising a computer having:
(i) a memory for receiving a database, the database comprising relative information in respect of a plurality of nodes or a plurality of particle pathways in the pre-determined portion;
(ii) means to receive input data from the process, and
(iii) means to calculate the at least one fluid flow parameter from the database and the input data.
In yet another of its aspects, an on-line UV dosimeter device for predicting bioassay equivalent dose for a given microorganism in a UV disinfection process, the UV disinfection process comprising a flow domain in which a fluid flows, the device comprising a computer having:
(i) a memory for receiving a database, the database comprising relative dose information in respect of a plurality of fluid pathways through the flow domain;
(ii) means to receive input data from the process, the input data selected from the group comprising UV transmittance of the fluid, flow rate of the fluid and intensity field in the fluid domain; and
(iii) means to calculate the bioassay equivalent dose for the given microorganism from the database and the input data.
In yet another of its aspects, the present invention provides a method for on-line prediction of at least one fluid flow parameter in a process, the process comprising a flow domain having disposed therein a pre-determined portion in which a fluid flows, the method comprising the steps of:
(i) storing in a memory of a computer a database, the database comprising relative information in respect of a plurality of nodes or a plurality of particle pathways in the pre-determined portion;
(ii) obtaining input data from the process;
(iii) conveying the input data to the computer; and
(iv) calculating the at least one fluid flow parameter from the database and the input data.
A fundamental understanding of a chemical, photochemical or biological process is key to predicting and controlling the process"" outcomes. Most of these types of processes involve fluid flow, and the behaviour of the fluid can significantly affect the efficiency of the process. The better the understanding of the fluid flow, the better the process prediction and control.
An advantage of the present invention is an online prediction of at least one fluid flow parameter such as velocity, pressure, temperature and turbulence parameters calculated preferably by computational fluid dynamics (CFD) and coupled with certain relevant parameters measured online at discrete points in the process of interest. If all of the relevant flow parameters are known throughout the flow domain of interest, a much better prediction of system response can be achieved, which leads to better process control.
For example, the invention can be applied to predicting dose distribution profiles in a UV radiation fluid treatment system thereby mitigating and/or obviating the above-mentioned disadvantages of the prior art. Of course, those of skill in the art will recognize that the present invention may be used in a variety of other applications such as photochemical processes, chemical processes, biological processes and the like.